NEUTRON SPECTRA MEASUREMENTS

Thermal neutron spectra were measured with timeof-flight techniques. Spectra were obtained for pure water and for a nearly homogeneous subcritical assembly where the ratio of themal absorption to high energy scattering cross section was t 125, 150, 175 0.3. For each medium, spectra were measured at 298 and 586 K. The experimental results are presented and compared with calculated theoretical spectra The agreement between theory and experiment is excellent for the multiplying media. On the basis of this agreement, one concludes that chemical binding effects in light water play a negligible role in determining the equllibrium neutron spectrum in water assemblies. (auth

Neutron time-of-flight measurements at the Rensselaer linac

Neutron transmission measurements of Ho, Er, Tm and Au samples have been made from thermal to several hundred eV and the data have been fitted with the SAMMY program. A 16-section NaI multiplicity detector has been used to measure simultaneously capture and scattering partial cross sections. These measurements are used to obtain accurate resonance parameters over this energy range for samples of Mo, Ho, Er, Tm and Au

EXPERIMENTAL DETERMINATION OF THE SPECTRA IN SEVERAL COLD WATER MODERATED ASSEMBLIES

Neutron spectra were obtained for a series of subcritical fuel assemblies with light water as moderator. It is concluded from the experimental results that the observed spectra are in reasonable agreement with the Wigner-Wilkins thermal neutron spectra calculations. (L.T.W.

Technique for fission measurements of highly active and weak cross-section actinides

The Rensselaer Intense Neutron Spectrometer (RINS) system provides an intense neutron source that is well suited for measuring the fission cross sections of microgram quantities of highly-active actinides and gram quantities of nuclei with very weak cross sections. The system consists of a 75-ton lead assembly driven by the RPI electron linac, and the neutron fluxes are three-to-four orders of magnitude more intense than those available in conventional time-of-flight measurements. Examples of measured cross sections of curium isotopes /sup 238/U and /sup 232/Th are presented. 17 refs., 10 figs., 1 tab

Neutron total and capture cross section measurements and resonance parameter analysis of tungsten from 0.01 to 200 eV

Natural tungsten metal has been measured using neutron time-of-flight spectroscopy at the Rensselaer Polytechnic Institute (RPI) Gaerttner LINAC Laboratory to improve the tungsten resonance parameters. Three separate types of measurements were performed; transmission, capture and self-indicating. Previous measurements did not employ all three experimental types and used less sophisticated analysis methods. It is the authors` conclusion that the current work improves on the published tungsten data base and reduces the resonance parameter uncertainties